Art of manufacturing square-bottom paper bags.



No. 720,366. A PATENT-ED FEB. 10, 1903, w. A. LORENZ. ART OF MANUFACTURING SQUARE BOTTOM PAPER BAGS.

APPLICATION FILED JAN. 2, 1901'.

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J W" W No. 720,366. PATBNTED- FEB. 10, 1903. W. A. LORENZ.

ART OF MANUFACTURING SQUARE BOTTOM PAPER BAGS.

APPLICATION FILED JAN. 2, 1901.

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Witnesses: 52 v p 1 2 fizz/ma UNITED STATES PATENT OFFICE.

'WILLIAM A. LORENZ, OF HARTFORD, CONNEQTICUT, ASSIGNOR TO UNION PAPER BAG MACHINE COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

ART OF MANUFACTURING SQUARE-BOTTOM PAPER BAGS.

SPECIFICATION forming part of Letters Patent No. 720,366, dated February 10, 1903.

Application filed January 2. 1901. Serial No. 41,896. (No model.)

To all whom it may concern: are gradually straightened out or stretched Be it known that 1, WILLIAM A. LORENZ, a by said devices the inside triangular folds will citizen of the United States, residing at Hartbe'fully developed. The process of straightford, in the county of Hartford and State of ening out or stretching the tucked sides is Connecticut, have invented certain new and usually carried out by swinging the devices useful Improvements in the Art of Manufac which engage the upper ply of the blank turing Square-Bottom Paper Bags, of which away from the devices engaging the lower the following is a full, clear, and exact speciply and substantially around the definingfication. line as an axis, the distance from each of said [O This invention relates to the art of manudevices to the defining-line remaining uni- 6o facturing square-bottom paper bags; audit form throughout this folding operation. In has for its object an improved'proces's of formpractice better results may be obtained when ing the so-called diamond fold in abellows-- thesides are stretched .out quickly, as comsided or tucked tube or blank, such process pared with the angular movement of the box- I 5 being adapted for usein connection with wellholders away from the tuck-holders-in other known methods of forming the tubular blank words, when said sides are straightened out and of subsequently pasting and folding the fully before the upper ply has been fully diamond of the blank to complete the bag. folded over. 7

My improved process has more particularly My improved process therefore comprises 20 for its object an easy and rapid manner of as one of its steps the engagement and openforming the inside triangular folds withing out of the upper and lower blank-plies at out subjecting the material to any excessive and between points which are at such disstrain, so that all liability of breaking the tance from the defining-line as to require only surface thereof or of tearing the same may be a comparatively small angular movement of 25 avoided. one relative to the other in order to stretch To this end my invention comprises as one out the tucked sides fully and then to permit of its features the process of opening out the the ply-engaging members gradually to move bottom-forming end of the tube or blank by toward the defining-line as the are or angustretching the sides thereof between certain lar movement of said members relative to 0 points on the upper and lower plies, the seveach other is increased until said members eral instrumentalities for holding said plies are in position at opposite sides of the definbeing caused to engage the same at .points ing-line and form nearly a straight line therewhich are more remote from the bottom-dewith, at which time the inside triangular folds fining line than is compatible with the proper have been fully developed.

35 form of said inside triangular folds, while A process incorporating my invention is during the operation of completing the diaclearlyillustrated in the accompanying drawmond form said points of engagement are ings, in which gradually shifted toward the defining-line. Figure 1 is a side view of a bag-blank, illus- When the so-called box form has been sub trating the manner in which the upper and o stantially developed, the inside triangular lower plies thereof are engaged by the foldfolds will not have assumed their required inginstrumentalities. Fig. 2 is a top view of form as yet, although the tucked sides have Fig. 1. Fig. 3 is an end view of the blank. been fully straightened out. Figs. -.t and 5 show the blank sides fully One of the common methods of forming the straightened out to form the box, the upper 45 diamond of a bag-blank comprises the enply having been partly folded around the de- 5 gagement of the upper and lower plies thereof fining-line from the position shown in Fig. 1 by suitable devices generallyknown as tuck to that shown in Fig. at, which represents a and box holders, these devices engagingsaid side View, while Fig. 5 is a top view of Fig. plies at a certain distance from the bottom- 4:. Figs. 6 and 7 show a further advance- 50 defining line, so that when the tucked sides ment in the folding operation and illustrate ICO the folding instrumentalities in slightly-contracted position while the tuck sides remain straightened out; and Figs. 8 and 9 show a side view and top view, respectively, of the blank when the folders have arrived at their final position and the diamond is substantially completed.

In the drawings the blank 10 is shown having tucked or bellows sides 30 and compris ing the bag-section A and the bottom-forming section A, the boundary-line between said sections being generally known as the defining-line and substantiated in the present instance by the edge at of the defining member D. Referring to Figs. 1 and 2, the upper ply 31 of the blank is illustrated engaged by the so-called box-holders (designated byB) and the proper function of which is to fold said upper ply around the defining edge d, while the lower ply 32 of the blank is engaged by the so-called tuck-holders T and the front diamond-holder F. In Fig. 2 the line of engagement heretofore employed between the working edges b of the box-holders l3 and t of the tuck-holders T is indicated by the dot-and-dash line 12, and the position of said working edges corresponded with this line throughout the folding operation in order to form the proper inside triangular folds commensurate with the depth of the tucks. Now it has been stated above that better results may be obtained by stretching out the tucked sides quickly as compared with the angular movement of the box-holders away from the tuck-holders, and in the present case I accomplish this end by so disposing the boxholders and tuck-holders that they will eugage the upper and lower plies, respectively, at such points thereof the distance of which from the defining-line is greater than the depth of the tucks, as is, for instance, shown in Fig. 2, in which dot-and-dash line 13 indicates the initial engaging position of the edges Z) and t of the box-holders B and the tuck-holders T, respectively. If the boxholders B are now swung away from the tuckholders T, substantially around the defining edge (1 as an axis, and said holders retain their positions relative to the upper and lower plies 31 32 of the blank, respectively, it will be clearly seen that the tucked sides will be stretched out until the position shown in Fig. 4 has been reached, when the sides 30 of the blank are fully distended, while, however, the are or angular movementbetween the box and tuck holders so far has been comparatively small. The so-called box is now completed, and in the further manipulation of the bagblank the angular movement of the box-holders will be continued in the direction of arrow 16, Fig. 4; but owing to the fact that the sides of the blank are already fully stretched out it follows that the box-holders must necessarily have a movement toward the tuck-holders as well and in the direction of the arrow 17. Inasmuch as the tuck-holders T engage the lower ply of the blank at points which correspend and coincide with those of the boxholders B, the tuck-holders also will have a movement toward the box-holders in the direction of arrow 18, so that when the folding operation has been continued to the position shown in Figs. 6 and 7 the distance between the engagement-points 22 and 23,respectively, from the edgedwill beless than that between the engagement-points 20 and 2l,respectively, (see Fig. 4,) from the said edge d.

As the folding operation is continued from the intermediate position (shown in Figs. 6 and 7) to the final position (shown in Figs. 8 and 9) the points of engagement on the plies will move toward each other until the distance of each of said points from the defining line or edge d equals the depth of the tucks, at which time the inside triangular folds assume their proper form. (See Fig. 8.) It should of course be remembered that during this operation the sides 30 of the blank will remain in fully-distended or stretched-out condition, so that the distance between the points 20 and 21 will be equal to that between the points 22 and 23, and, furthermore, on continuing the folding operation, also equal to the distance between the points 24 and 25 (see Fig. 9) when the box-holders have been swung over to their final position and the diamond is substantially formed. By comparison of Fig. 2 or Fig. 5 with Figs. 6 and Sin the ordernamed the shifting movement of the points of engagement may be clearly seen, and since in the present instance the starting position of the box-holders coincides with that of the tuckholders, as shown in Fig. 2, both holders engaging their respective tube-plies at points equidistant from the defining edge d,the shifting movement of the box-holders must correspond to that of the tuck-holders, and, as is illustrated in Fig. 8, from the line 13 to 12', so as to develop the inside triangular folds into their proper form.

While in the present case the holders have preferably an angular movement from the line 13 to the line 12, such a movement need need not necessarily take place, the particular object of the invention being a shifting movement of the points of engaging the plies of the tubeas, for instance, from the points 26 to the points 27 thereof. Likewise it is obvious that the same result may be obtained if only one of the engagementpoints be shifted toward the other or if the amounts of shifting movement of both points should vary, provided, however, that the distance between the holders be decreased to the proper amount during the diamond-forming operation and that said points are substantially equidistant from the defining-line at the end of said operation.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. The process of forming the diamond of square-bottom paper bags from bellows-sided tubing, which comprises a complete distention of the tucked sides at such points between the end of the blank and the definingline, the distance of which from the defining line is greater than the depth of the tucks, and shifting such points after such distention while completing the diamond fold.

2. The process of forming the diamond of square-bottom paper bags from bellows-sided tubing, which comprises the engagement of the sides of the upper and lower tube plies at points, the distance of which from the defining-line is greater than the depth of the tucks; stretching out the tucked sides between such points, and subsequently shifting said points of engagement toward the defining-line to develop the triangular folds into their proper form.

3. The process of forming the diamond of square-bottom paper bags from bellows-sided tubing, which comprises the engagement of the sides of the upper and lower tube plies at such points the distance of which from the defining-line is greater than the depth of the tucks; stretching out the tucked sides between such points to form the box, and subsequently shifting such points of engagement toward the defining-line, while, at the same time, the points of engagement are brought to positions at opposite sides of the definingline, to develop the inside triangular folds into their proper form.

4. The process of forming the diamond of square-bottom paper bags from bellowssided tubing which comprises the engagement of the sides of the upper and lower tube plies, at points, the distance of which from the defining-line is greater than the depth of the tucks, and the complete distention of the tucked sides preparatory to developing the inside triangular folds into their proper form, and then shifting said points of engagement toward each other during the completion of the diamond.

5. The process of forming a diamond of square-bottom paper bags from bellows-sided tubing which comprises the engagement of the upper and lower tube plies at such points,

the distance of which from the defining-line is greater than the depth of the tucks, completely distending the tucked sides between such points preparatory to developing the inside triangular folds into their proper form, and then decreasing the distance between said points of engagement, while at the same time said points are brought to positions at opposite sides of the defining-line to develop the inside triangular folds into their proper form.

WILLIAM A. LORENZ.

Witnesses: v

CHAS. F. SOHMELZ, NELLIE PHOENIX. 

